U.S. Pat. No. 7,298,860 discloses a system for enabling the assembly and suspension of a plurality of loudspeakers in a line array where the splay angle between the adjacent speakers can be adjusted and rigidly maintained. The line array system utilizes rigging frames that allow for the coupling and supporting of the loudspeakers through the use of adjustable hinge bars. The rigging frames and adjustable hinge bars together form and rigidly maintain the splay angles between adjacent loudspeakers and correspondingly the curvature of the line array speaker assembly.
An issue with this disclosure is that two pins 714 must be used to adjust the splay angle between adjacent line array speakers (col. 7, lines 18-30). Having to use two pins to adjust the splay angle increases the cost and complexity of this system.
U.S. Pat. No. 8,130,996 discloses loud speakers which are equipped with, on their back sides, a mount for connectors with which the individual loud speakers can be connected to one another. The mount comprises two legs that are attached to the back side of the loud speaker box and enclose a channel in which the connector is displaceably movable. At its one end the mount has a row of holes for receiving a pin that extends through a hole on one end of a connector belonging to the adjacent loud speaker box and has at its other end a manually actuated spring-loaded snap-in pin. The snap-in pin is insertable through another hole disposed in front of the other end of the connector. One guide unit on each side of the snap-in pin limits the channel and are arranged perpendicular to the direction of movement of the connector and form guides for the connector.
An issue with this disclosure is that the connector 4 only has a single hole 13 that is designed and intended to be aligned with one of the holes 9 for securing the connector 4 to the mount in which the holes 9 are located. Note that the blind hole 16 in connector 4 is designed and intended to only be used when the loud speaker is put in the transport position after the loud speaker box group has been disassembled. As such, a total of nine holes (one hole 13 and eight holes 9) are used to obtain eight different positions between two speakers. If, for example, three holes 13 and three holes 9 were used instead, a total of nine different positions between the two speakers could be obtained with only six total holes.
U.S. Pat. No. 7,634,100 discloses a side frame for a loudspeaker rigging system has links associated with the frame structure for linking together the corners of the frame structures of vertically adjacent side frames. The links associated with each side frame structure include a pivot link and splay adjustment link, each of which has a top extended end and a base end with a seating edge. Guide channels, which are located in the top corner regions of the frame structure to receive the base ends of a pivot link and splay adjustment link associated with a vertically adjacent side frame, have seating surfaces that conform to the seating edges at the base ends of the pivot and splay adjustment link. When base ends of these links seat in the guide channels, pin holes in the base end of the links self-align with pin holes in the corners of the frame structure for easy insertion locking pins. The extended end of the splay adjustment link further includes at least two, and preferably an array of pin holes which can selectively be matched with one pin hole within a row of pin holes in a bottom corner region of the side frame to permit adjustments of the splay angle over a range of angles. Suitably, two rows of pin holes are provided in the top extended end of the splay adjustment link to permit multiple and incrementally small splay angle adjustments.
This arrangement requires a side frame and splay adjustment link on each side of each speaker which adds greatly to the cost and complexity of this loudspeaker rigging system. It also requires holes spaced out perpendicular to the primary direction of adjustment, which adds greatly to the space required.